Thermoelectric-based thermal management of electrical devices

ABSTRACT

Disclosed embodiments include thermoelectric-based thermal management systems and methods configured to heat and/or cool an electrical device. Thermal management systems can include at least one electrical conductor in electrical and thermal communication with a temperature-sensitive region of the electrical device and at least one thermoelectric device in thermal communication with the at least one electrical conductor. Electric power can be directed to the thermoelectric device by the same electrical conductor or an external power supply, causing the thermoelectric device to provide controlled heating and/or cooling to the electrical device via the at least one electrical conductor.

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Application PCT/US2014/011339, filed Jan. 13, 2014, titledTHERMOELECTRIC-BASED THERMAL MANAGEMENT OF ELECTRICAL DEVICES, whichclaims the benefit of U.S. Provisional Application No. 61/752,353, filedJan. 14, 2013, titled THERMOELECTRIC-BASED THERMAL MANAGEMENT OFELECTRICAL DEVICES, the entirety of each of which is incorporated hereinby reference.

BACKGROUND

Field

This disclosure relates generally to thermoelectric (TE) cooling andheating of electrical devices.

Description of Related Art

Power electronics and other electrical devices, such as batteries, canbe sensitive to overheating, cold temperatures, extreme temperatures,and operating temperature limits. The performance of such devices may bediminished, sometimes severely, when the devices are operated outside ofrecommended temperature ranges. In semiconductor devices, integratedcircuit dies can overheat and malfunction. In batteries, including, forexample, batteries used for automotive applications in electrifiedvehicles, battery cells and their components can degrade when overheatedor overcooled. Such degradation can manifest itself in reduced batterystorage capacity and/or reduced ability for the battery to be rechargedover multiple duty cycles.

SUMMARY

It can be advantageous to manage the thermal conditions of powerelectronics and other electrical devices. Thermal management can reduceincidences of overheating, overcooling, and electrical devicedegradation. Certain embodiments described herein provide thermalmanagement of devices that carry significant electric power and/orrequire high current and efficiency (e.g., power amplifiers,transistors, transformers, power inverters, insulated-gate bipolartransistors (IGBTs), electric motors, high power lasers andlight-emitting diodes, batteries, and others). A wide range of solutionscan be used to thermally manage such devices, including convective airand liquid cooling, conductive cooling, spray cooling with liquid jets,thermoelectric cooling of boards and chip cases, and other solutions. Atleast some embodiments disclosed herein provide at least one of thefollowing advantages compared to existing techniques for heating orcooling electrical devices: higher power efficiency, lower or eliminatedmaintenance costs, greater reliability, longer service life, fewercomponents, fewer or eliminated moving parts, heating and cooling modesof operation, other advantages, or a combination of advantages.

In electrical devices, typically electrically active portions and/ortemperature sensitive regions of the device are connected to the outsideworld, such as, for example, external circuits or devices, viaelectrical conductors. For example, electrodes of a battery cell can bedesigned to carry high electric power without significant losses (e.g.,heat losses that are proportional to the square of the current, perJoule's Law). The wire gauge of the electrical conductors used for suchelectrodes is commensurate with the high current that typically flows insuch devices. The larger the size of the battery is, the bigger are theelectrode posts for connection with outside circuits.

The high electrical conductance of electrodes and many other types ofelectrical conductors also means that such conductors typically havehigh thermal conductivity. The high thermal conductivity can be used tosolve various thermal management problems, where one can deliver desiredthermal power (e.g., cooling, heating, etc.) directly to the sensitiveelements of the device by heating and/or cooling the electrodes,bypassing thermally-insensitive elements of the device. Similar to usingthermally conditioned blood during blood transfusions for deliveringheat deep to the core of human bodies, heat pumping through theelectrodes can be used to efficiently deliver desired thermal conditionsdeep inside an electrical device. As an example, it has been determinedthat electrode cooling of advanced automotive batteries is one of themost advantageous techniques for battery thermal management. Forexample, the electrodes can be cooled using solid, liquid, or aircooling techniques. In a sense, electrodes act as cold fingers in such athermal management arrangement.

Embodiments disclosed herein include systems and methods capable ofthermally managing an electrical device by applying direct or indirectthermoelectric (TE) cooling and/or heating to current carryingelectrical conductors (e.g., electrodes) of power components,electronics, and other electrical devices. Such devices can oftenbenefit from thermal management. Some embodiments will be described withreference to particular electrical devices, such as, for example,batteries. However, at least some embodiments disclosed herein arecapable of providing thermal management to other electrical devices,such as, for example, insulated-gate bipolar transistors (IGBTs), otherelectrical devices, or a combination of devices. At least some suchdevices can have high current carrying capacity and can suffer fromoperation outside of a preferred temperature range. The operation ofsome embodiments is described with reference to a cooling mode ofoperation. However, some or all of the embodiments disclosed herein canhave a heating mode of operation, as well. In some situations a heatingmode of operation can be employed to maintain the temperature of anelectrical device above a threshold temperature, under which theelectrical device may degrade or exhibit impaired operation. TE devicesare uniquely suited to provide both heating and cooling functions withminimum complications for system architecture.

Embodiments disclosed herein include thermoelectric-based thermalmanagement systems and methods. In some embodiments, a thermalmanagement system is configured to manage temperature in atemperature-sensitive region of an electrical device. The thermalmanagement system can include a thermoelectric device configured totransfer thermal energy between a main surface and a waste surface uponapplication of electric power to the thermoelectric device. In someembodiments, the main surface of the thermoelectric device is insubstantial thermal communication with a heat exchange surface of anelectrical conductor. The electrical conductor is configured to deliverelectric power to or from an electrical device such that the electricalconductor serves as a conduit for conducting thermal energy between atemperature-sensitive region of the electrical device and thethermoelectric device.

In certain embodiments, a method for thermally managing an electricaldevice includes connecting a heat transfer device that comprises anelectrically conductive portion and an electrically insulating portionto a plurality of electrical conductors of an electrical device. Themethod can include directing substantial thermal energy exchange betweenthe heat transfer device and a main surface of a thermoelectric device.

In some embodiments, a method for thermally managing an electricaldevice includes establishing substantial thermal communication between athermoelectric device and a heat exchange surface of an electricalconductor that is in thermal and electrical communication with theelectrical device. The method can include heating or cooling theelectrical device by adjusting the current directed in or out of thethermoelectric device.

In some embodiments, a thermal management system is provided that isconfigured to manage temperature in a temperature-sensitive region of anelectrical device. The system includes a thermoelectric deviceconfigured to transfer thermal energy between a main surface and a wastesurface upon application of electric power to the thermoelectric device,wherein the main surface of the thermoelectric device is in substantialthermal communication with an electrical conductor. The electricalconductor is configured to deliver electric power to or from anelectrical device, and is capable of serving as a conduit for conductingthermal energy between a temperature-sensitive region of the electricaldevice and the thermoelectric device. The system includes a controllercomprising a control algorithm configured to monitor a thermal gradientcreated during operation of the electrical device across the temperaturesensitive region and to adjust electric power delivered to thethermoelectric device such that the thermal energy transferred to oraway from the temperature-sensitive region of the electrical devicereduces or eliminates the thermal gradient created during operation ofthe electrical device across the temperature sensitive region.

In some embodiments, the thermal management system includes a sensor inthermal communication with the electrical device and in electricalcommunication with the controller. The controller is configured tomonitor an input from the sensor and electric current directed in or outof the electrical device under thermal management and adjust electricpower delivered to the thermoelectric device to reduce or eliminate thethermal gradient created during operation of the electrical deviceacross the temperature sensitive region.

In some embodiments, the electric power delivered to the thermoelectricdevice in response to the input to reduce or eliminate the thermalgradient created during operation of the electrical device across thetemperature sensitive region is adjusted between two or more nonzerolevels of electric power.

In some embodiments, the control algorithm is further configured tomonitor a thermal gradient produced as a result of the thermal energytransferred to or away from the temperature sensitive region of theelectrical device and to adjust electric power delivered to thethermoelectric device such that the thermal gradient produced as aresult of the thermal energy transferred to or away from the temperaturesensitive region of the electrical device reduces or eliminates thethermal gradient created during operation of the electrical deviceacross the temperature sensitive region.

In some embodiments, the thermoelectric device comprises a firstoperating mode and a second operating mode. In the first operating mode,the thermoelectric device is configured to transfer a maximum amount ofthermal energy allowed by the thermoelectric device. In the secondoperating mode, the thermoelectric device is configured to transfer anamount of thermal energy such that the thermal gradient created by thetransfer of thermal energy balances with the thermal gradient createdduring operation of the electrical device across the temperaturesensitive region to reduce or eliminate a resultant thermal gradientacross the temperature sensitive region.

In some embodiments, an input configured to be monitored by thecontroller comprises at least one of: temperature of the electricaldevice, charge state of the electrical device, health of the electricaldevice, voltage of the electrical device, resistance of the electricaldevice, current of the electrical device, load on the electrical device,temperature of an environment, weather forecast, time of day, terraininformation, and geometry of the temperature sensitive region.

In some embodiments, the controller is integrated with a batterymanagement system configured to administer control functions to abattery pack.

In some embodiments, the electrical device is a battery, and thetemperature sensitive region is a cell of the battery.

In some embodiments, a resultant thermal gradient across the temperaturesensitive region of the electrical device is reduced to less than orequal to about 10 degrees C. In some embodiments, the thermoelectricdevice is powered by the electrical device.

In some embodiments, a method for thermally managing an electricaldevice includes establishing substantial thermal communication between athermoelectric device and an electrical conductor that is in thermal andelectrical communication with a temperature sensitive region of anelectrical device. The method includes monitoring an input from atemperature sensor in thermal communication with thetemperature-sensitive region of the electrical device and electricalcommunication with a controller that includes a control algorithmprovided to monitor the input. The input includes a thermal gradientcreated during operation of the electrical device across the temperaturesensitive region. The method includes adjusting the current directed inor out of the thermoelectric device in response to the input to reduceor eliminate a thermal gradient created during operation of theelectrical device across the temperature sensitive region.

In some embodiments, adjusting the current directed in or out of thethermoelectric device in response to the input to reduce or eliminate athermal gradient created during operation of the electrical deviceacross the temperature-sensitive region comprises adjusting the currentbetween two or more nonzero levels.

In some embodiments, the control algorithm is configured to monitor athermal gradient produced as a result of the thermal energy transferredto or away from the temperature sensitive region of the electricaldevice and to adjust current delivered to the thermoelectric device suchthat the thermal gradient produced as a result of the thermal energytransferred to or away from the temperature sensitive region of theelectrical device combines with the thermal gradient created duringoperation of the electrical device across the temperature sensitiveregion such that a resulting thermal gradient of the electrical deviceis eliminated or reduced.

In some embodiments, the method further includes operating thethermoelectric device in a first mode and a second mode. In the firstmode, the thermoelectric device is configured to transfer a maximumamount of thermal energy allowed by the thermoelectric device. In thesecond operating mode, the thermoelectric device is configured totransfer an amount of thermal energy such that the thermal gradientcreated by the transfer of thermal energy balances with the thermalgradient created during operation of the electrical device across thetemperature sensitive region to reduce or eliminate a resultant thermalgradient across the temperature sensitive region.

In some embodiments, an input configured to be monitored by thecontroller comprises at least one of: temperature of the electricaldevice, charge state of the electrical device, health of the electricaldevice, voltage of the electrical device, resistance of the electricaldevice, current of the electrical device, load on the electrical device,temperature of an environment, weather forecast, time of day, terraininformation, and geometry of the temperature sensitive region.

In some embodiments, the controller is integrated with a batterymanagement system configured to administer control functions to abattery pack.

In some embodiments, the electrical device is a battery, and thetemperature sensitive region is a cell of the battery.

In some embodiments, the thermal gradient across the temperaturesensitive region of the electrical device is reduced to less than orequal to about 10 degrees C.

In some embodiments, the thermoelectric device is powered by theelectrical device.

In some embodiments, a method of manufacturing a thermal managementsystem for thermally managing an electrical device is provided thatincludes connecting a thermoelectric device to an electrical conductorthat is in thermal and electrical communication with a temperaturesensitive region of an electrical device. The method includespositioning a sensor on the electrical device such that the sensor iscapable of measuring an input comprising a thermal gradient of thetemperature sensitive region of the electrical device. The methodincludes connecting the sensor to a control system comprising a controlalgorithm configured to adjust electric power delivered to thethermoelectric device in response to the input from the sensor such thatthermal energy transferred to or away from the temperature sensitiveregion of the electrical device reduces or eliminates a thermal gradientcreated during operation of the electrical device across the temperaturesensitive region.

In some embodiments, the control algorithm is further configured tomonitor a thermal gradient produced as a result of the thermal energytransferred to or away from the temperature sensitive region of theelectrical device and to adjust electric power delivered to thethermoelectric device such that the thermal gradient produced as aresult of the thermal energy transferred to or away from the temperaturesensitive region of the electrical device combines with the thermalgradient created during operation of the electrical device across thetemperature sensitive region such that a resulting thermal gradient ofthe electrical device is eliminated or reduced.

In some embodiments, the input from the sensor comprises at least oneof: temperature of the electrical device, charge state of the electricaldevice, health of the electrical device, voltage of the electricaldevice, resistance of the electrical device, current of the electricaldevice, load on the electrical device, temperature of an environment,weather forecast, time of day, terrain information, and geometry of thetemperature sensitive region.

In some embodiments, the method includes integrating the control systemwith a battery management system configured to administer controlfunctions to a battery pack

In some embodiments, the electrical device is a battery, and thetemperature sensitive region is a cell of the battery.

In some embodiments, the thermal gradient across the temperaturesensitive region of the electrical device is reduced to less than orequal to about 10 degrees C.

In some embodiments, the thermoelectric device is configured to bepowered by the electrical device.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments are depicted in the accompanying drawings forillustrative purposes, and should in no way be interpreted as limitingthe scope of the thermoelectric assemblies or systems described herein.In addition, various features of different disclosed embodiments can becombined with one another to form additional embodiments, which are partof this disclosure. Any feature or structure can be removed, altered, oromitted. Throughout the drawings, reference numbers may be reused toindicate correspondence between reference elements.

FIGS. 1A and 1B schematically illustrate examples of a thermalmanagement system with multiple TE devices, where each of the TE devicesis in thermal communication with an electrical conductor of anelectrical device.

FIG. 2 schematically illustrates an example thermal management systemwith a TE device in thermal communication with two electrical conductorsof an electrical device.

FIG. 3 schematically illustrates an example thermal management systemwith a TE device in thermal communication with electrodes of a batteryvia a heat transfer device.

FIG. 4 schematically illustrates an example thermal management systemwith an electronic control unit (ECU) configured to control heatingand/or cooling provided to an electrical device.

FIG. 5 schematically illustrates an example thermal management systemwith an external power supply.

FIG. 6 illustrates an example method for controlling heating and/orcooling provided to an electrical device by a thermal management system.

FIG. 7A schematically illustrates an example electrical configuration ofa thermal management system.

FIG. 7B schematically illustrates another example electricalconfiguration of a thermal management system.

FIG. 8A schematically illustrates an example thermal management systemconnected to an electrical device receiving electric power.

FIG. 8B schematically illustrates an example thermal management systemconnected to an electrical device providing electric power to a load.

FIG. 9 is a cross-sectional perspective view of an electrical conductorin thermal communication with a TE device.

FIG. 10A is a cross-sectional view of a thermal management system with aheat concentrator.

FIG. 10B is a cross-sectional view of a thermal management system with aheat spreader.

FIG. 11 is a cross-sectional view of thermal management system with acurved TE device.

FIG. 12 is another cross-sectional view of a thermal management systemwith a curved TE device.

FIG. 13 schematically illustrates an example thermal management systemwith a thermal insulator connected electrically in-line with externalleads.

FIG. 14 schematically illustrates an example battery pack includingcells electrically connected in series.

FIG. 15 schematically illustrates an example thermal management systemthat connects adjacent cells of the battery pack of FIG. 14.

FIG. 16 schematically illustrates another example thermal managementsystem.

FIG. 17 schematically illustrates an example method for heating and/orcooling an electrical device.

FIG. 18 schematically illustrates an example thermal management system.

FIG. 19 schematically illustrates an example thermal management systemwith a heat sink.

FIG. 20 is a perspective view of an example thermal management system.

FIG. 21 is an end view of the thermal management system of FIG. 20.

FIG. 22 is a perspective view of another example thermal managementsystem.

FIG. 23 is an end view of the thermal management system of FIG. 22.

FIG. 24 is a perspective view of another example thermal managementsystem.

FIG. 25 is an end view of the thermal management system of FIG. 24.

FIG. 26 is a perspective view of another example thermal managementsystem.

FIG. 27 is a close-up view of a portion of the thermal management systemof FIG. 24.

FIG. 28 is a close-up view of a portion of the thermal management systemof FIG. 26.

FIG. 29 schematically illustrates an example thermal gradient of a cellof a battery.

FIG. 30 schematically illustrates simplified views of an example batterycell having a reduced thermal gradient due to the net effect ofcombining thermal gradients produced due to the operation and thermalmanagement of the battery cell.

FIG. 31 schematically illustrates an example thermal management system.

FIG. 32 illustrates an example method for controlling heating and/orcooling provided to an electrical device by a thermal management system.

DETAILED DESCRIPTION

Although certain embodiments and examples are disclosed herein, thesubject matter extends beyond the examples in the specifically disclosedembodiments to other alternative embodiments and/or uses, and tomodifications and equivalents thereof. Thus, the scope of the claimsappended hereto is not limited by any of the particular embodimentsdescribed below. For example, in any method or process disclosed herein,the acts or operations of the method or process may be performed in anysuitable sequence and are not necessarily limited to any particulardisclosed sequence. Various operations may be described as multiplediscrete operations in turn, in a manner that may be helpful inunderstanding certain embodiments; however, the order of descriptionshould not be construed to imply that these operations are orderdependent. Additionally, the structures, systems, and/or devicesdescribed herein may be embodied as integrated components or as separatecomponents. For purposes of comparing various embodiments, certainaspects and advantages of these embodiments are described. Notnecessarily all such aspects or advantages are achieved by anyparticular embodiment. Thus, for example, various embodiments may becarried out in a manner that achieves or optimizes one advantage orgroup of advantages as taught herein without necessarily achieving otheraspects or advantages as may also be taught or suggested herein.

It can be advantageous to manage the thermal conditions of electronicsand electrical devices. Such thermal management can reduce incidences ofoverheating, overcooling, and electrical device degradation. Certainembodiments described herein provide thermal management of devices thatcarry significant electric power and/or require high current andefficiency (e.g., power amplifiers, transistors, transformers, powerinverters, insulated-gate bipolar transistors (IGBTs), electric motors,high power lasers and light-emitting diodes, batteries, and others). Awide range of solutions can be used to thermally manage such devices,including convective air and liquid cooling, conductive cooling, spraycooling with liquid jets, thermoelectric cooling of boards and chipcases, and other solutions. At least some embodiments disclosed hereinprovide at least one of the following advantages compared to existingtechniques for heating or cooling electrical devices: higher powerefficiency, lower or eliminated maintenance costs, greater reliability,longer service life, fewer components, fewer or eliminated moving parts,heating and cooling modes of operation, other advantages, or acombination of advantages.

In electrical devices, typically electrically active portions and/ortemperature sensitive regions of the device are connected to the outsideworld, such as, for example, external circuits or devices, viaelectrical conductors. For example, electrodes of a battery cell can bedesigned to carry high electric power without significant losses (e.g.,heat losses that are proportional to the square of the current, perJoule's Law). The wire gauge of the electrical conductors used for suchelectrodes is commensurate with the high current that typically flows insuch devices. The larger the size of the battery is, the bigger are theelectrode posts for connection with the outside circuits.

The high electrical conductance of electrodes and many other types ofelectrical conductors also means that such conductors typically havehigh thermal conductivity. The high thermal conductivity can be used tosolve various thermal management problems, where one can deliver desiredthermal power (e.g., cooling, heating, etc.) directly to the sensitiveelements of the device by heating and/or cooling the electrodes,bypassing thermally-insensitive elements of the device. Similar to usingthermally conditioned blood during blood transfusions for deliveringheat deep to the core of human bodies, heat pumping through theelectrodes can be used to efficiently deliver desired thermal conditionsdeep inside an electrical device. As an example, it has been determinedthat electrode cooling of advanced automotive batteries is one of themost advantageous techniques for battery thermal management. Forexample, the electrodes can be cooled using solid, liquid, or aircooling techniques. In a sense, electrodes act as cold fingers in such athermal management arrangement.

Embodiments disclosed herein include systems and methods capable ofthermally managing an electrical device by applying direct or indirectthermoelectric (TE) cooling and/or heating to current carryingelectrical conductors (e.g., electrodes) of power components,electronics, and other electrical devices. Such devices can oftenbenefit from thermal management. Some embodiments will be described withreference to particular electrical devices, such as, for example,batteries. However, at least some embodiments disclosed herein arecapable of providing thermal management to other electrical devices,such as, for example, insulated-gate bipolar transistors (IGBTs), otherelectrical devices, or a combination of devices. At least some suchdevices can have high current carrying capacity and can suffer fromoperation outside of a preferred temperature range. The operation ofsome embodiments is described with reference to a cooling mode ofoperation. However, some or all of the embodiments disclosed herein canhave a heating mode of operation, as well. In some situations a heatingmode of operation can be employed to maintain the temperature of anelectrical device above a threshold temperature, under which theelectrical device may degrade or exhibit impaired operation. TE devicesare uniquely suited to provide both heating and cooling functions withminimum complications for system architecture.

There are a variety of ways in which TE devices can be used forelectrical conductor cooling and/or heating tasks. As described herein,TE devices can include one or more TE elements, TE assemblies and/or TEmodules. In some embodiments, a TE system can include a TE device, whichcomprises a first side and a second side opposite the first side. Insome embodiments, the first side and second side can be a main surfaceand waste surface or heating surface and cooling surface. A TE devicecan be operably coupled with a power source. The power source can beconfigured to apply a voltage to the TE device. When voltage is appliedin one direction, one side (e.g., the first side) creates heat while theother side (e.g., the second side) absorbs heat. Switching polarity ofthe circuit creates the opposite effect. In a typical arrangement, a TEdevice comprises a closed circuit that includes dissimilar materials. Asa DC voltage is applied to the closed circuit, a temperature differenceis produced at the junction of the dissimilar materials. Depending onthe direction of the electric current, heat is either emitted orabsorbed at a particular junction. In some embodiments, the TE deviceincludes several solid state P- and N-type semi-conductor elementsconnected in series. In certain embodiments, the junctions aresandwiched between two electrical isolation members (e.g., ceramicplates), which can form the cold side and the hot side of the TE device.The cold side can be thermally coupled to an object (e.g., electricalconductor, electrical device under thermal management, etc.) to becooled and the hot side can be thermally coupled to a heat sink whichdissipates heat to the environment. In some embodiments, the hot sidecan be coupled to an object (e.g., electrical conductor, electricaldevice under thermal management, etc.) to be heated. Certainnon-limiting embodiments are described below.

FIGS. 1A-1B illustrate schematics of example thermal management systems1. In some embodiments, a thermal management system 1 can include atleast one TE device 6 a, 6 b in substantial thermal communication with aheat exchange surface of at least one electrical conductor 4 a, 4 b(e.g., a current carrying connector, an electrode, portion of a cell,terminal wires, wiring between electrodes or portions of cells, leads,etc.) of an electrical component or device 2 (e.g., power amplifiers,transistors, transformers, power inverters, insulated-gate bipolartransistors (IGBT's), electric motors, high power lasers andlight-emitting diodes, batteries, etc.). The term “substantial thermalcommunication” is used herein in its broad and ordinary sense andincludes, for example, snug contact between surfaces at the thermalcommunication interface; one or more heat transfer materials or devicesbetween surfaces in thermal communication; a connection between solidsurfaces using a thermally conductive material system, wherein such asystem can include pads, thermal grease, paste, one or more workingfluids, or other structures with high thermal conductivity between thesurfaces; other suitable structures; or a combination of structures.Substantial thermal communication can take place between surfaces thatare directly connected or indirectly connected via one or more interfacematerials.

In some embodiments, at least one TE device can be connected to anelectrical device under thermal management. In some embodiments, atleast one TE device can be in substantial thermal communication with(e.g., contact, attached to, etc.) an electrical component, part,portion or device under thermal management. In such instances, theelectrical conductors can conduct both electrical energy and thermalenergy between temperature-sensitive regions of the electrical deviceand one or more external devices. When operated in a cooling mode, theheat Q is pumped from the electrical conductors 4 a, 4 b (and from theelectrical device 2) as shown by arrows 8 a, 8 b in FIG. 1A anddissipated into the outside environment, which can be air, liquid,another solid component, or a combination of components. When operatedin the heating mode, the thermal power will be pumped in the reversedirection, delivering the heat into the electrical device 2 through theelectrical conductors 4 a, 4 b as shown by arrows 8 a, 8 b in FIG. 1B.

FIGS. 1A-1B show separate TE devices 6 a, 6 b that inject or remove heatQ from separate electrical conductors 4 a, 4 b, respectively. In someembodiments, a single TE device 6 can be used to control (e.g., be insubstantial thermal communication with) two or more electricalconductors 4 a, 4 b as illustrated in FIG. 2. In some embodiments, oneor more electrical conductors can be in substantial thermalcommunication with no TE devices. In some embodiments, the TE devicesare in substantial thermal communication with the electrical conductors.In some embodiments, this substantial thermal communication can beaccomplished by a direct attachment of the TE device to the electricalconductor, or by using an efficient thermal or heat transfer device 10or thermally conductive apparatus (e.g., a surface of a heat exchanger,a heat pipe, shunt or heat plane) positioned between the electricaldevice 2 under thermal management and surface 12 of the TE device 6, asillustrated in FIG. 3. In some embodiments, the thermal transfer device10 can be attached to, directly or indirectly contact at least oneelectrical conductor 4 a, 4 b and/or at least one TE device 6.

As shown in FIGS. 1A, 1B, and 2, in some embodiments, a thermalmanagement system 1 can include at least one TE device 6, 6 a, 6 b. Asurface 12 a, 12 b of the TE device 6, 6 a, 6 b can be in direct orindirect contact with a solid surface 14 a, 14 b of at least oneelectrical conductor 4 a, 4 b. The electrical conductor 4 a, 4 b can beconfigured to deliver electric power to an electrical device 2 such thatthe electrical conductor 4 a, 4 b also serves as a conduit forconducting thermal energy between temperature-sensitive regions (e.g.,heat Q) in the electrical device 2 and the TE device 6, 6 a, 6 b. Insome embodiments, the interface between the surface 12 a, 12 b of TEdevice 6, 6 a, 6 b and solid surface 14 a, 14 b can include a thermallyconductive material system (not shown) configured to facilitatesubstantial thermal communication between the surfaces. For example, thethermally conductive material system can include grease, paste, pads,material with high thermal conductivity, material with thermalconductivity greater than or equal to about 100 W/(m×K), anothersuitable material, or a combination of materials. In some embodiments, athermally conductive material system can be positioned at an interfacebetween one or more surfaces of a thermal transfer device and surfacesof a TE device and/or electrical conductor.

In some embodiments, a fluid connection can be configured between,around and/or through the TE device 6, 6 a, 6 b and at least oneelectrical conductor 4 a, 4 b that is used to facilitate the transfer ofelectric power to or out of the electrical device 2. In someembodiments, a working fluid can be used to facilitate the transfer ofthermal energy between an electrical device 2 and a TE device 6, 6 a, 6b.

A controller can be provided to control the TE device to perform eithera heating or cooling function and/or adjust the electric power deliveredto the TE device. The TE device can be powered inline with the deviceunder thermal management or via an external power supply or source. Insome embodiments, TE devices are electrically powered and controlled toperform their heat pumping function to and/or from a device underthermal management. The power and control function can be performed by aseparate electronic control unit, ECU 40. The ECU 40 can adjust theelectric power delivered to the TE device 44 associated with the TEmanagement of the device 46. In some embodiments, the ECU 40 takesinputs from one or more temperature sensors 42 that sense the thermalcondition of the device 46 directly or via electrical conductors (notshown), compares them to algorithms and issues a controlling signal forthe TE device 44 to perform either a heating or cooling function, asillustrated in the FIG. 4. In some embodiments, the ECU 40 can beconfigured to take inputs other than temperature (e.g., the currentpushed in and/or out to the TE device 44 and/or device 46, etc.) fromother sensors (not shown) and adjust the cooling and/or heating outputto/from the device 46. The controller may be integrated with the rest ofthe electronics supporting the device under thermal management. Forexample, if such device is a battery pack, then it is typicallyoutfitted with a Battery Management System, or BMS, which is configuredto monitor the health of the battery and/or administer control functionsin response to internal and/or external changes. The TE controllerfunctionality can be integrated into the BMS and can be co-located onthe same printed circuit board or using the same chipsets that performBMS functions.

The steps an example thermal management system can undergo in someembodiments to actively thermally manage an electrical device areillustrated in FIG. 6. In the first step 60 a, sensors can be configuredto monitor the thermal condition and electric current directed in or outof the device under thermal management. The second step 60 b, includesadjusting the electric power delivered to the TE device associated withthe thermal management of the device. In a third step 60 c, changes inelectric current and temperature of the electrical conductor aremonitored. Steps 60 a-60 c can be repeated.

In some embodiments, to facilitate such temperature control, it can behelpful to determine the ambient temperature, the temperature of atleast one of the sides of a TE device and/or a temperature within the TEdevice. Thus, some embodiments of a TE system can include one or more, acombination, or none of the following: an ambient temperature sensor, aTE device temperature sensor (such as a thermistor) located inside,adjacent to, near, or otherwise in close proximity to the TE deviceand/or the like.

However, some embodiments including one or more TE device temperaturesensors can be less desirable due to, for example, the cost of thesensor, the additional manufacturing steps and complexity associatedwith positioning the sensor in the system, the possibility of sensorfailure, thermal lag and/or one or more other reasons or considerations.In some embodiments, a thermal management system can include a powersource operably coupled with a TE device having first and second sidesand does not include a temperature sensor to determine the temperatureof one of the sides of the TE device and/or the device under thermalmanagement. Rather, the thermal management system is configured todetermine the temperature of one of the first and second sides (or atemperature differential across the TE device) by the potential inducedby the Seebeck effect.

In certain embodiments, the power source can be turned off (e.g., supplyzero volts to the TE device). In such instances, a temperaturedifference between the first and second sides can induce a potentialbetween the first and second sides. The inducement of this potential isknown as the Seebeck effect. The potential produced is generallyproportional to the temperature difference between the first and secondsides and can be expressed by the following equation:V=α(Th−Tc)=αΔTWhere V is the potential between the first and second sides, a is theSeebeck coefficient, and (Th−Tc) or ΔT is the temperature differencebetween the first and second sides. As such, the Seebeck coefficient fora given TE device can be described as the ratio of the potential to thetemperature difference between the first and second sides.

In some cases, the Seebeck coefficient α can be determinedexperimentally. In certain configurations, for a TE system with a knownSeebeck coefficient α, the temperature difference between the first andsecond sides can be determined based on the voltage potential. Such aconfiguration can, for example, provide for monitoring of thetemperature difference of the TE device without the need for a separatetemperature sensor. As noted above, the elimination of such atemperature sensor can facilitate manufacturing (e.g., reduce processsteps), decrease manufacturing time, reduce costs, increase devicelongevity, and/or provide one or more other advantages or benefits.Further, not including of such a sensor can simplify the design of theTE device, for example, by eliminating channels through the TE devicefor the passage of wires for the sensor. Furthermore, not including sucha sensor can improve reliability of the system by reducing the totalnumber of components that could fail.

In some embodiments, the thermal management system is configured todetermine an absolute temperature of at least one of the sides of the TEdevice. In some embodiments, an ECU is in communication with an ambienttemperature sensor and is configured to determine the potential. Forexample, an analog input of the ECU can be in communication with anegative temperature coefficient device or other device, from which asignal can be used to determine (e.g., by a calculation) an ambienttemperature. Such a configuration can, for example, allow for thedetermination of an absolute temperature of at least one of the firstand second sides of the TE device. For example, the absolute temperaturecan be determined with a calculation or by correlating the potentialwith a known (e.g., by empirical measurements) absolute temperature forat least one of the first and second sides.

In some embodiments, the temperature difference and/or the absolutetemperature of at least one of the sides is used in a feedback controlscheme, which can, for example, provide for a faster response timeand/or reduced thermal lag for temperature feedback compared to systemsemploying a separate temperature sensor.

In some embodiments, the temperature difference and/or the absolutetemperature of at least one of the sides is used for fault monitoring.For example, the temperature difference and/or the absolute temperatureof at least one of the sides can be used to detect overheating of the TEdevice, which could reduce the efficiency of the TE device or otherwisedamage the device and/or other components of the thermal managementsystem.

In some embodiments, each of the TE devices can be powered by a powersource, which can selectively provide electric power to each of thedevices. In certain embodiments, the TE devices share a common powersource. In other arrangements, the TE devices each has a dedicated powersource.

In some embodiments as illustrated in FIG. 4, the electric power to a TEdevice 44 is decoupled from the electric power flowing to/from thedevice 46 under thermal management. As shown in FIG. 5, in someembodiments, an external power supply 48 not under TE management (e.g.,an external battery, etc.) can be configured to supply power to the ECU40 and/or the TE device 44. However, in some embodiments, a TE device 76can be powered in-line with the electrical conductors 74 a, 74 b of adevice 76 under thermal management. In some embodiments, a fraction(≤100%) of the electric current that flows through the device 72 underthermal management can also flow directly through the TE device 76 asillustrated in some embodiments in FIGS. 7A-7B. In some embodiments, theTE device 76 can be in an electrical parallel or series connection withthe device 42 relative to the rest of the circuit, as illustrated inFIGS. 7A and 7B respectively.

In some embodiments, for example a parallel connection as illustrated inFIG. 7A, only a fraction of the current is flowing through the TE device76 (the value depends on the ratio of the resistances of TE device andthe load). In some embodiments, for example a series connection asillustrated in FIG. 7A, all current flows through TE device 76.

In some embodiments, the benefit of such an in-line arrangement of TEpower is the simplification (and cost reduction) of control circuitry. ATE device 76 is powered and pumping heat away from (or to) the device 72whenever the electric power is flowing through the device 72. Therefore,by sizing the heat pumping capacity of the TE device 76 appropriatelyand relative to the range of possible operating conditions, it ispossible to use such a “built-in” control of thermal condition of thedevice 72 under management. No separate thermal sensing of the batterycondition is needed.

The inline connection and control scheme can be used when one mode of TEoperation is desired (e.g., cooling). In such arrangements, electriccurrent flows in one direction. The inline connection and control schemecan also be used when the mode of operation (e.g., heating or cooling)is consistent with the direction of current flow. This is largely thecase with power electronics or devices, but could be different in thecase of batteries. In batteries, often both heating and cooling areneeded depending on the ambient conditions, and also the direction ofcurrent flow depends on whether the battering is operating in a chargingmode or a discharging mode.

In some embodiments, one or more diodes or other electric currentcontrol devices can be positioned along the conductor between anelectrode and a TE device. Such current control devices can beconfigured to prevent an undesired operating mode from occurring duringcharging or discharging of the device under thermal management. Incertain such embodiments, the thermal management system can beconfigured to perform only a cooling mode of operation or only a heatingmode of operation, regardless of the direction of current flow (e.g.,charging or discharging) to the electrical device. Such embodiments canbe beneficial, for example, when environmental conductions, propertiesof the device, or other factors make only one mode of operation desired.

A TE device can be positioned closer to or further from the device underthermal management depending on the application. In some embodiments,from the thermal management point of view, it is beneficial to locatethe heat pump (e.g., TE device) as close to the device that is beingthermally managed as possible. Such localization results in the mostefficient use of thermal management, avoiding unnecessary thermal andelectric losses. For example, in case of power electronics it isdesirable to locate a heat management system as close to the heat source(e.g., semiconductor junction) as possible.

However, in some cases, the TE device can be located further away fromthe device for the benefit of improved system logistics. In such cases,the TE device is still capable of cooling the power leads. An example ofsuch trade-off is a battery 82 operating either in charging ordischarging conditions and a TE device connected in an in-line fashionas described above. The direction of current is opposite between the twomodes of battery operation. In this application, one or more TE devices86 can be incorporated in the charger side 88 a of the battery chargerand in the load side 88 b of the battery connector 84. Such connectionschemes are illustrated in FIGS. 8A-8B. The difference between the twoconnections illustrated in FIGS. 8A-8B is the polarity of the TE device86. By switching the polarity between the two modes it can be alwaysensured that the battery 82 is being cooled in both charging anddischarging modes, independently of the current flow direction.

A similar polarity switch function can be achieved by using a single TEdevice 86 and a relay or switch (not shown) that changes the polarity ofthe electric current flow through the TE device in response to change ofthe direction of current flow in a battery 82. However, in someapplications, persistent cooling of the battery 82 is desired, e.g., inrapid charging. In some embodiments, the TE devices can be built intothe connectors 84 on the cable side of the battery charger. The polarityof TE devices in this case should be appropriate to cool the leadsduring charging.

A TE device or module can be constructed into various geometries, shapesand sizes. A typical TE device is a flat or planar module with twoparallel surfaces. One of the most common sizes of such modules is 40×40mm with thickness ranging below a millimeter to multiple millimeters.The heat is removed from one surface and moved to the other. A change indevice polarity changes the direction of heat flow. A myriad of otherdevice sizes is available on the commercial market. Typically, the sizeof the device is application-specific and matched to electrical andthermal impedances of the system.

Such flat modules can be either directly applied to electrodes that needto be cooled, provided that the electrodes have appropriately sized flatsections. FIG. 9 illustrates an example thermal management systemconfiguration 90 with a flat TE module 92 in substantial thermalcommunication with an electrical conductor, e.g., an electrode 94 havinga flat surface 96.

Alternatively, at least one intermediate heat spreader 98 a or heatconcentrator 98 b made of materials with high thermal conductivity(e.g., copper, aluminum, etc.) may be positioned between TE device 92and the electrode 94 to match the geometrical size differences, asillustrated in FIGS. 10A-10B.

In some embodiments, another option for mating TE devices and electrodesor other electrical conductors is to change the shape of a TE device 92from flat to cylindrical, essentially concentric with or surrounding theelectrode 94, as illustrated in FIG. 11. In this case, the heat would bemoved away from (or to) the electrode radially which is potentially amore optimal thermal management path. Other non-planar shapes notlimited to cylindrical can also be used.

Such a cylindrical TE device may be implemented in a variety of ways.One solution is to implement a high power density T-shunt architectureas described in U.S. Pat. No. 6,959,555, which is incorporated byreference in its entirety. In some embodiments, individual p- and n-typethermoelectric elements 120 a, 120 b can be located in a ring patternaround the electrode 124, as illustrated in FIG. 12. Alternatively, pand n semiconductors can be made as a full ring as opposed to smallerpellets. The inner, smaller diameter shunts 126 can act as heatexchangers communicating with the cooled electrodes 124. The outer,larger diameter shunts 128 can act as fins discharging waste heat intothe air surrounding the cooled electrode.

An insulator can be used to thermally insulate an electrical deviceunder thermal management and help prevent heat from passing through tothe rest of a circuit via external leads. In some embodiments, thethermal management of electrical devices can suffer from a problem ofparasitic losses because if the electrical conductors (e.g., terminals)are cooled, then some of the cooling does not go towards the deviceunder thermal management but rather leaks through the wires or leadstowards the rest of the circuit. In other words, the external leads actas thermal conductors that act as a thermal load parallel to the deviceunder thermal management in relation to the TE device.

In order to minimize the parasitic effect of such leaks, a thermalinsulator 130 positioned between TE device 132 and the rest of thecircuit can be introduced as illustrated in FIG. 13. Such a thermalinsulator 130 (or multitude of insulators, e.g., one or more per lead)can be connected electrically in-line with the external leads 134. Insome embodiments, electric current can flowing freely, or with minimalpenalty, through such an insulator 130. Thermally, however, theinsulator has very low thermal conductivity, so that the heat does notpass through it efficiently. “Q” is the amount of heat flowing to/fromthe device under thermal management and/or external leads. Large Qsignifies large flow of heat and/or cooling power.

There are a number of possible physical implementations of a thermalinsulator. In some embodiments, a thermally insulating material has highelectrical conductivity and low thermal conductivity. One good type ofmaterial satisfying these requirements is thermoelectric material. Forexample, thermoelectric materials can be used as thermal insulators inan application of electrical feed through for superconductive magnets,such as described by Yu. Ivanov et al., Proceedings of InternationalConference on Thermoelectrics, Shanghai, 2010. However, the insulatordoes not have to be made of TE material, as in this application theSeebeck performance of the insulator material is not necessarilyimportant. Other examples could be electrically conductive ceramics,conductive foams or other materials.

Cooling and heating of multiple electrical devices or components inelectrical communication with each other can be provided by a thermalmanagement system. A number of discrete electronic components that mayrequire thermal management can be connected in series or in parallelelectrically. For example, a battery pack can be built by connecting aplurality of individual cells in series electrical communication. Theexample described below uses a battery pack as an example of a systemunder thermal management. The features described, however, are notlimited to thermal management of batteries only and are applicable tothermal management of other electronic components or electrical devices.

In some embodiments, a thermal management system can include a batterypack including N cells 140 a-140 c connected in series as depicted inFIG. 14. The individual cells can have different shapes and internalconstruction, such as cylindrical, prismatic, pouch or other cellpackaging types.

Thermal management of individual cells 140 a-140 c by at least one TEdevice 146 a, 146 b can be especially effective when applied toelectrical leads or internal wires 148 that connect adjacent cells, asopposed to thermal management through the terminal wires that bringelectric current in and out of the battery pack. FIG. 15 illustrates oneembodiment of TE devices 146 a, 146 b directly connected to orcontacting such internal wires 148 that connect the individual cells 140a-140 c.

In this configuration in some embodiments, when TE devices 146 a, 146 bare thermally connected to internal wires 148 that connect adjacentcells 140 a-140 c, substantially all of the thermal energy is deliveredinside and/or extracted from the cells. This is distinctly differentfrom an arrangement when a TE device 186 is thermally connected to aterminal or external wire 180 that connects the battery 182 with otherelements. In the latter case, a part of the thermal energy 184 canescape through the wire 180 away from the battery 182, and the overallsystem level thermal management efficiency can be diminished. Suchadverse effect is depicted in FIG. 18.

In some embodiments, a thermal management system is configured tothermally manage only the connections that are internal to the batterypack or other electrical device. For example, battery pack embodimentsdisclosed herein having cells connected in series can have thisconfiguration. This thermal management approach can be applied to anyarrangement of individual elements in the pack provided that onlyinternal wires are thermally managed. The thermal management can beapplied substantially only to electrical connections that originate andterminate inside the pack, and not to the connections that connect thepack to the rest of the system.

The individual elements can be connected in series, in parallel, or evenbelong to independent electric circuits. Additionally, in someembodiments, a single TE device can be in substantial thermalcommunication with a single cable connecting adjacent cells, or aplurality of such cables, therefore spreading the thermal managementacross several cells.

In some embodiments, all electrical conductors can be connected to atleast one TE device. In some embodiments, at least one electricalconductor or component is not connected to a TE device. For example, asillustrated in FIG. 15, cell 140 a only has one internal wire 148connected to a TE device 146 a. The other internal wire is not connectedto a TE device. In some embodiments, all the internal wires of a cell orelectrical component are not connected or in thermal communication witha TE device. In some embodiments, one or more entire cells, internalwires, or electrical conductors are not connected to any TE device. Forexample, in some embodiments, cells closer to the center of the batteryare connected to at least one TE device while outer cells of the batteryare not connected to at least one TE device. Individual electricalconductors can have independent thermal couplings with TE devices.

In some embodiments, a thermal management system can control orthermally manage individual cells or groups of cells. Such embodimentscan permit a thermal management controller to control the temperature ofelectrical conductors or components independently from other conductorsor components of the electrical device. In certain such embodiments,thermal control can be localized to the cell level. In some suchembodiments, the thermal management system is configured to minimize orreduce cell to cell variation, avoid or reduce cell degradation, and/orallow for independent thermal management tuning.

As illustrated in FIG. 16, in some embodiments, a thermal managementsystem can include a controller 142. The controller can be connectedwith TE devices 146 a-146 c. In some embodiments, each of TE devices 146a-146 c can be connected to at least one electrical conductor 148 a-148c of cells 140 a-140 c. Each of the cells 140 a-140 c can be thermallycontrolled by the system independently of one another. The electricpower directed to or out of each TE device 146 a-146 c that providesheating and/or cooling to the cells 140 a-140 c can be varied, changed,or adjusted for each TE device and/or cell independently of another TEdevice and/or cell.

FIG. 17 illustrates an example method for independently controlling thetemperature of multiple temperature-sensitive regions (e.g., batterycells) of an electrical device. The method can include determining thethermal management regime for 2 or more independent current carryingelectrical conductors (170 a). Independent thermal management can beapplied to each cell using a thermal management system (170 b). Electricpower supplied to at least one of thermal management systems can beadjusted independent of electric power supplied to the other thermalmanagement systems (170 c).

In some embodiments, a heat pipe can be provided as a waste heattransport mechanism. Waste heat from a TE device can be dissipated in aheat sink. Examples of heat sinks include heat exchangers, wastestreams, other structures for dissipating heat, and combinations ofstructures. A heat sink can be attached to the waste side or surface ofthe TE device. The heat sink can be cooled by air, liquid, or,alternatively, it can be a solid member connecting the TE device with abigger solid heat sink such as a battery case, car frame, or anotherstructural element that dissipates heat effectively. However, inpractical applications, such as, for example, a battery thermalmanagement system, there can be packaging constraints that limit thepossibility of bringing the cooling media close to the waste side of theTE device. Alternatively, a heat or thermal transport device may be usedto move the heat from the waste side of the TE device to anotherlocation where heat dissipation may be implemented effectively.

In some embodiments, a heat transfer device 198 can be used to connectthe waste side or surface of the TE device 196 to a heat sink 194 wherethe heat is ultimately dumped by, for example, air, liquid, or solid, asillustrated in FIG. 19. Such a heat sink can be for example the liquidcooling circuit of the car, a radiator or an air cooled heat sink,ambient air, working fluid, fluid reservoir, or a solid body (e.g.,battery case or car frame).

FIGS. 20-28 illustrate other embodiments of thermal management systemconfigurations for cooling and/or heating electrical, electronic, andpower devices and/or components such as, for example, a battery orbattery pack. These embodiments can be combined with or comprise one ormore of any of the features and embodiments described above. Asdiscussed above, a battery pack can include one or more cells connectedin series and/or parallel. The thermal management system can be used tocool and/or heat the electrical conductors of the battery directly orindirectly.

FIGS. 20-21 illustrate an embodiment of a thermal management systemincluding a battery pack 200 having multiple cells 204 electricallyconnected with one another to provide a single functional battery pack200. In some embodiments, individual cells of the battery 202 can beelectrically connected together in series via electrically conductivebars or other connectors. In some embodiments, the thermal managementsystem can include one or more thermoelectric devices 206 integratedwith or connected to (e.g., in substantial thermal communication with)one or more terminals 212 of one or more cells 204 of the battery 202.As illustrated in FIG. 20, in one embodiment, the cells 204 connected inseries can have two parallel rows of terminals 212 that extend along atop surface of the battery 202. In some embodiments, the terminals 212include positive and negative terminals (e.g., anodes and cathodes). Incertain such embodiments, the positive and negative terminals arespatially positioned in an alternating arrangement. The thermoelectricdevice 206 can have a copper substrate 208 layered on a ceramicsubstrate 210 or any other suitable configuration. In some embodiments,one end or portion of each thermoelectric device 206 can be connected toor integrated with at least one terminal 212 of two adjacent cells 204that are connected in series. In some embodiments, at least one terminal212 is not in substantial thermal communication with or connected to atleast one TE device 206. Another end or portion of each thermoelectricdevice 206 can be connected, clipped, adhered, bonded, clamped, orotherwise attached to a heat transfer device 214. The heat transferdevice 214 can be, for example, a liquid tube heat exchanger. In someembodiments, one heat transfer device 214 can be attached to eachthermoelectric device 206 or to all of the TE devices. In otherembodiments, multiple heat transfer devices 214 can be attached or insubstantial thermal communication with each thermoelectric device 206.

As illustrated in FIGS. 20-21, in some embodiments, the heat transferdevice 214 can extend along at least a portion of the top surface of thebattery 202 between the two parallel rows of terminals 212. In certainembodiments, the terminals are not in parallel rows. FIG. 21 illustratesthat in some embodiments, the heat transfer device 214 can be positionedsuch that it does not directly contact or touch a surface of the battery202. In certain embodiments, the heat transfer device 214 can be indirect contact with the battery or surfaces of the battery 202. In someembodiments, the ceramic substrate 210 interfaces with the heat transferdevice 214 and provides support or robustness. The copper substrate 208can carry the current draw of the battery 202. In some embodiments, theheat transfer device 214 can include both electrically conductiveportions and electrically insulating portions. In some embodiments, theelectrically conductive portions can extend toward each other.

FIGS. 22-23 illustrate another configuration of a thermal managementsystem for cooling and/or heating an electrical device such as abattery. In one embodiment, the thermal management system can have twoheat transfer devices 234 a, 234 b, each of which extends along a topside of the thermoelectric devices (not shown) that are connected to thetwo generally parallel rows of terminals 232 a, 232 b. The heat transferdevices 234 a and 234 b can each extend along one row of terminals 232a, 232 b. In some embodiments, the heat transfer devices 234 a and 234 bor other heat transfer devices can be positioned between the terminals232 a, 232 b and the TE devices.

FIGS. 24-28 illustrate another configuration of a thermal managementsystem for cooling and/or heating a power device such as a battery. Insome embodiments, one or more heat transfer devices can be positioned orspaced apart from one another as far as possible based on the geometryof the electrical conductors, heat transfer devices, and/or device underthermal management. In some embodiments, at least one heat transferdevice can be positioned on a surface of an electrical device that isdifferent from a surface that the electrical conductors protrude from.In some embodiments, at least one heat transfer device is not positionedon the same plane as the electrical conductors of an electrical device.Thermal transfer can occur on a surface perpendicular, normal,non-planar and/or non-parallel to the surface the electrical conductorsprotrude from. In some embodiments, one or more heat transfer devices254 a and 254 b are positioned on two opposing sides of the battery 242.The heat transfer devices 254 a and 254 b can extend along substantiallythe entire length or side of the battery 242. One end of thethermoelectric devices 246 can be in substantial thermal communicationwith at least one terminal 252 of two adjacent cells 244 that areconnected in series.

In some embodiments, the ends of the thermoelectric devices 246 can beconnected or mounted to the tops of the terminals 252 as illustrated inFIGS. 24-25, and 27. In some embodiments, portions of thermoelectricdevices can surround an outer perimeter of an electrical conductor or bemounted to the sides as illustrated in FIGS. 26 and 28. In someembodiments, portions of thermoelectric devices can contact a topsurface of an electrode in a substantially planar manner. In someembodiments, an overall height or footprint of a battery module or otherelectrical device can be maintained or kept substantially equivalent byorienting or connecting structures of a thermal management system in asubstantially planar manner with the existing surface or surfaces ofelectrical conductors or electrical devices.

In some embodiments, the other end of each thermoelectric device 246 canbe connected, clipped, and/or clamped to a heat transfer device 254 a or254 b. In some embodiments, such a thermal management systemconfiguration can transfer heat to or from the terminals 252 and/or thesides of the battery 242.

In some embodiments, at least some thermal management systems that aredescribed herein can include one or more of the following features:

-   -   1. Direct thermal management of power electronics or electrical        devices by thermally managing the leads of the devices via a TE        device.    -   2. Indirect lead cooling with heat transfer device connected to        a TE device.    -   3. At least one cooled power lead per TE device.    -   4. Multiple cooled leads by a single TE device.    -   5. TE device powered in parallel or in series with the thermally        managed device.    -   6. TE voltage-current design optimized for connecting directly        to the battery to minimize the need for extra electronics and to        provide a desired amount of cooling for the battery.    -   7. TE device on the battery side of the disconnect.    -   8. TE device on the charger cable side of the disconnect.    -   9. Different polarity TE devices between charger cables and        battery side use so that the battery is always being cooled        whether it is charged or discharged.    -   10. Thermal insulator that prevents parasitic flow of heat/cold        towards the portion of the electrical circuit outside of the        device being thermally managed.    -   11. A device under thermal management that includes at least two        units connected in series. A TE device can be thermally        connected to the electrical conductor that connects the two        units in series.    -   12. A plurality of elements connected electrically between each        other. At least one TE device can be connected thermally to a        plurality of electrical conductors that connect the elements.    -   13. Battery pack thermal management using one or more of the        techniques described above.    -   14. IGBT thermal management using one or more of the techniques        described above.    -   15. Thermal management of power amplifiers using one or more of        the techniques described above.

FIGS. 29-32 illustrate other embodiments of thermal management systemconfigurations for cooling and/or heating electrical devices, e.g. abattery, battery pack, etc., that can comprise or incorporate featuresand aspects, in whole or in part, of any of the embodiments, features,structures and operating modes discussed herein.

As discussed above, in some embodiments, it can be beneficial to providethermal management (either heating and/or cooling) to an electricaldevice to promote efficient operation of the electrical device. Forexample, heating and cooling an electrical device (e.g. a battery,battery pack, cells of a battery pack, etc.) through electricalconductors (e.g., battery or cell electrodes) can be an efficient way toperform such thermal management. One option to provide distributed andagile thermal management to the cells in a battery pack is to controlthe flow of heat in and out of the battery by putting thermoelectricdevices in thermal communication with one or more battery electrodes asdescribed in certain embodiments herein.

Generally, when a cell of a battery or battery pack is operational(e.g., charging or discharging), internal chemical and/or physicalprocesses generate heat in the cell. In certain embodiments, this heatcan be distributed inhomogeneously across the cell, resulting in thehottest areas of the cell being closest, in near proximity to, or at theelectrodes. For example, such a pattern or thermal gradient wasdescribed in S. Chacko, Y. M. Chung/Journal of Power Sources 213 (2012)296-303. A schematic illustration of a simulated profile of thetemperature or thermal gradient of a discharging battery from the ChackoArticle is shown in FIG. 29. The different hash patterns indicatedifferent temperatures. In some embodiments, as shown in FIG. 29, thetemperature gradient of the cell is such that it decreases in acontinuous manner from volumes or zones 340 in close proximity to or atthe electrodes 300 with the highest temperatures to zones 360 on the endof the cell farthest away from the electrodes with the lowesttemperatures. In some embodiments, the temperature gradient is such thatthe temperature increases from volumes or zones in close proximity to orat the electrodes with the lowest temperatures to zones on the cellfarthest away from the electrodes with the highest temperatures.

In some embodiments, temperature or thermal gradients across or withinthe battery cell or other temperature sensitive region of an electricaldevice are produced a result of the heat produced, added, or absorbed bythe electrochemical process within the cell and by Joule heating duringoperation (e.g., discharging or charging). Joule heating can result fromthe operation of a battery which generates heat due to the I²R losses ascurrent flows through the internal resistance of the battery duringcharging or discharging.

These are bulk processes occurring in the volume of the cell anddiffusion has a large contribution to where in the cell volume theprocess occurs at a particular time. For example, in some embodiments,when the cell is close to full charge, the discharge will begin close toor in near proximity to the electrodes. In such embodiments, more heatis produced closer to the electrodes, resulting in higher temperaturesat or near these electrodes than regions or zones of the cell fartheraway from the electrodes. Conversely, in some embodiments, when thebattery is close to depletion, the zones farthest away from electrodesare the warmest or have higher temperatures relative to the zones nearthe electrodes because they have not discharged yet.

Additionally, in some embodiments, when a cell of a battery or region ofanother electrical device is heated or cooled through or via theelectrodes, a thermal gradient can also be established across the cellor region. For example, if the electrodes are cooled (i.e. thermalenergy is extracted from the cell), the volume, zone, region, etc. ofthe cell that is closest or in near proximity to the electrodes iscooled the most. If the rate of heat extraction from the cell issignificantly higher than the rate of heat production in the cell(caused by physical and/or chemical processes occurring when the cell isoperational as discussed above) then a thermal gradient will develop inthe cell. The areas proximal to the electrodes will be coldest while theareas distal to the electrodes will be the warmest. For example, in oneembodiment, 20 W of heat was pumped out of a pouch cell (e.g., Actacell,5 A-h power cell), leading to the creation of a thermal gradient acrossthe cell of 13 degrees C. Conversely, if the electrodes are heated, aninverse gradient may be established, where the areas proximal to theelectrodes are the warmest and the areas distal to the electrodes arethe coldest.

In some embodiments, the gradation of thermal energy is not a discretevariation but a continuous thermal gradient across the cell of thebattery or region of the electrical device. Thermal gradients can reducecell life, capacity and long-term cycling ability. In some embodiments,it is beneficial to eliminate, minimize, or reduce such gradients.

In some embodiments, combining the two effects (gradients created bycooling and/or heating through electrodes and gradients created duringelectrical or battery operation (e.g., due to electrochemical process,Joule heating, etc)) so that the gradients balance or counter-act oneanother can result in a cell of a battery or region of an electricaldevice wherein the net, overall and/or resultant thermal gradient iseliminated, minimized, or reduced. In some embodiments, the thermalmanagement system is configured to control the thermal gradient acrossor within the region of the electrical device such that the thermalgradient remains less than or equal to about 2° C., less than or equalto about 10° C., or less than or equal to about 30° C.

One example of combining thermal gradients produced by operation andthermal management of an electrical device such that the net, resultingor overall thermal gradient reduction is reduced or minimized isschematically illustrated in FIG. 30. The first drawing on the left inFIG. 30 schematically illustrates a simplified view of a thermalgradient created by heat generated in a battery cell by internalprocesses (e.g., electrochemical, Joule heating, etc.) during operation.The thermal gradient or variation in localized temperatures indicated bydifferent hatching patterns across the cell of the battery, illustratethat in some embodiments, the highest temperatures are near theelectrode and the lowest temperatures in regions farthest away from theelectrode. The middle drawing of FIG. 30 schematically illustrates asimplified view of a thermal gradient that is produced by controlledcooling of an electrical device via an electrode of the cell which is inthermal communication with a thermoelectric device. The thermal gradientis inverse relative to that of the thermal gradient in the first drawingwith the highest temperatures in regions of the cell farthest away fromthe electrode and lowest temperatures near the electrode as illustratedby different hatching patterns. Combining the two effects or thermalgradients, results in a cell or region of an electrical device with anoverall or net thermal gradient reduced, minimized or eliminated asillustrated in right drawing of FIG. 30.

Referring now to FIG. 31, an embodiment of a thermal management system301 is provided that can comprise various features and advantages of theaforementioned embodiments (e.g., as illustrated in FIGS. 1-28), as wellas other features discussed herein. Thermal management system 301 can beconfigured to provide controlled cooling and/or heating to reduce,minimize, or eliminate thermal gradients, localized hotspots, and/orcold spots formed across or within a temperature sensitive region of anelectrical device (e.g., cell of a battery, etc.) The thermal managementsystem 301 can be configured such that it comprises a controlled coolingand/or heating system that accounts for uneven distribution of generatedheat, temperature effects, and/or thermal hotspots and cold spots in anelectrical device as a result of internal heating produced duringoperation, ambient temperatures, and/or geometry of the region. Thecontrolled cooling and/or heating system can account for such variablesalong with other electrical aspects that produce uneven temperaturedistribution or thermal gradients across the region of the electricaldevice. The thermal management system 301 can apply controlled coolingand/or heating as necessary or that is adequate to counteract, accountfor or balance any such thermal gradient or temperature distribution. Insome embodiments, the thermal management system can apply or providecontrolled cooling and/or heating that produces an inverse thermalgradient across the region of the electrical device that counteracts orbalances the thermal gradient produced during operation of theelectrical device.

In some embodiments, as illustrated in FIG. 31, a thermal managementsystem 301 can be configured to manage temperature in atemperature-sensitive region 302 of an electrical device 304. The system301 can comprise a thermoelectric device 306 configured to transferthermal energy between a main surface 308 and a waste surface 318 of thethermoelectric device upon application of electric power to thethermoelectric device 306. The main surface 308 of the thermoelectricdevice can be in substantial thermal communication with an electricalconductor 310. The electrical conductor 310 is configured to deliverelectric power to or from the electrical device 304 such that theelectrical conductor 310 serves as a conduit for conducting thermalenergy between the temperature-sensitive region 302 of the electricaldevice 304 and the thermoelectric device 306. As discussed andillustrated in other embodiments, the electrical device 304 can be, butis not limited to, a battery, battery pack, etc. The temperaturesensitive region 302 can be, but is not limited to, a cell or cells of abattery. In some embodiments, the electrical conductor 310 can be anelectrode of a battery or cell. The thermoelectric device can contact orabut the electrical conductor 310 or a heat transfer device that isthermal communication with the electrical conductor as discussed abovewith respect to certain embodiments.

In some embodiments, the thermal management system 301 can comprise acontroller or control system 312 (e.g., but not limited to, anelectronic control unit that can comprise various features andadvantages of the aforementioned embodiments discussed above, as well asother features discussed herein) configured to adjust electric powerdelivered to the thermoelectric device 306 such that the thermal energytransferred to or away (e.g., heating and/or cooling) from thetemperature-sensitive region 302 of the electrical device 304 via theelectrical conductor 310 reduces, minimizes or eliminates a thermalgradient created during operation of the electrical device 304 acrossthe temperature sensitive region 302.

As discussed above, in some embodiments, the controller or controlsystem 312 can adjust the electric power level (e.g., voltage and/orcurrent, etc.) delivered to or away from the thermoelectric device 306such that the thermal energy transferred to or away from thetemperature-sensitive region 302 of the electrical device 304 produces athermal gradient across or within the region. In some embodiments, theelectric power directed to or away from the thermoelectric device isadjusted between two or more nonzero levels of current and/or voltage.The controller or control system 312 can be configured (e.g., with acontrol algorithm) such that the thermal gradient produced as a resultof the heating and/or cooling of the region counterbalances or combineswith a thermal gradient produced during operation of the electricaldevice 304 such that a resulting, net or overall thermal gradient of theelectrical device is eliminated or reduced as illustrated in simplifiedviews in FIG. 30.

In some embodiments, the thermal handling capacity of the thermoelectricdevice is designed or configured to be adequate to remove the heatproduced in a cell or region of an electrical device during operation.The thermoelectric management system 301 can comprise a controller orcontrol system 312 (e.g., electronic control unit, etc) that regulatesthe operation of the thermoelectric device 306 in response to thethermal condition of the cell, its current mode of operation, the inputsfrom pack-level signals, inputs from a sensor and/or other inputs asdescribed herein. As a result, the thermoelectric device 306 can pumpaway the heat produced in a cell, thereby neutralizing, minimizing,reducing or eliminating the thermal gradient produced by cell operation.In some embodiments, the thermoelectric device 306 can pump heat to thecell as necessary to reduce a thermal gradient.

In some embodiments, the controller or control system 312 can comprisean electronic control unit that provides real time control of thethermoelectric device 306 so that the heat pumping rate (either to oraway) of the thermoelectric device 306 responds to the heat productionrate of the cell to reduce, minimize, or eliminate a thermal gradient.Additionally, the control algorithm may incorporate a variety of otherinputs 316 to be monitored by the controller 312, including, forexample:

-   -   state of charge, state of health, voltage, temperature,        resistance or combination of these and other operational        parameters of the electrical device, battery pack, module or        individual cell;    -   performance of the thermoelectric device as a function of        operational parameters (for example, a thermoelectric device may        be operated in the most efficient mode or the most powerful mode        depending on the needs of the battery);    -   outside environmental information such as temperature, time of        day, season, weather forecast;    -   terrain information (for example, driving in the mountains        creates extra load on the battery which can be anticipated if        terrain information is supplied from on-board GPS);    -   The electronic control unit may be a standalone electronic        circuit, or it could be a part of the overall Battery Management        System, BMS;    -   Geometry of the temperature-sensitive region to be managed

In some embodiments, as discussed above the thermoelectric device 306and/or the controller 312 (e.g., electronic control unit) may be fullyor partially powered by the exact cell or electrical device of whichthermal condition is being managed as illustrated in FIG. 4. In otherembodiments, the electric power may be provided from other sources suchas an external power supply as discussed above with aforementionedembodiments as illustrated in FIG. 5.

In some embodiments, the thermoelectric management system 301 cancomprise a sensor(s) 314 with one or more features as discussed abovewith respect to FIGS. 4-5. As illustrated in FIG. 31, the sensor(s) 314can be in thermal communication with the electrical device 304 and inelectrical communication with the controller 312 and provide any of theinputs as described above to be monitored by the controller or controlsystem 312. Inputs or signals 316 from other sensors (not shown) canalso be provided to the controller or control system 312 to be monitoredas part of a control algorithm to provide sufficient heating and/orcooling to reduce, minimize or eliminate a thermal gradient or otheruneven temperature distribution.

In some embodiments, the heat pumping capacity of a thermoelectricdevice attached to the electrodes is a function of the battery type andits construction, as well as construction of the battery pack. A typicalpouch cell of several A-h electric power capacity can require athermoelectric device with heat pumping capacity between 1 and 10 W.

The thermal management system 301 can comprise any of the features asdiscussed above in the aforementioned embodiments. For example, thethermal management system 301 can be combined with the independentcontrol features illustrated and described with respect to FIG. 16.Individual cells and/or regions of the battery or electrical device canbe thermally managed independently. In some embodiments, differentregions will have different thermal gradients and thus will needindependent control such that the appropriate or sufficient heatingand/or cooling is provided to reduce or eliminate any thermal gradientproduced or created during operation. In some embodiments, each regionor cell can be monitored by or be in communication with one or moredifferent sensors. In some embodiments, one or more sensors can monitoror be in communication with one or more regions or cells. In someembodiments, the thermal management system can comprise bulk monitoringwherein the thermal condition of the entire battery or electrical deviceis monitored by one or more sensors. In some embodiments, one or moresensors can provide a report of the thermal condition or other input ofthe entire electrical device or battery to the controller. Additionally,the thermal management system 301 can be combined with, but is notlimited to, any of the configurations illustrated in FIGS. 20-28.

In some embodiments, as illustrated in FIG. 32, steps 380A-380C forthermally managing an electrical device are provided. The electricaldevice can have electrical conductors (e.g., electrodes, etc.) connectedto a thermoelectric device. The first step 380A can comprise monitoringthe thermal condition of the electrical device as a whole, in part, orindividual cells or regions independently. The second step 380B cancomprise directing electrical power (e.g., voltage and/or current, etc.)to the thermoelectric device to produce a desired heating and/or coolingeffect. The third step 380C can comprise adjusting the level of electricpower directed to the thermoelectric device based on the thermalcondition of the electric device. In some embodiments, the steps cancomprise establishing substantial thermal communication between athermoelectric device and an electrical conductor that is in thermal andelectrical communication with a temperature-sensitive region of theelectrical device. The steps can comprise monitoring inputs provided bya sensor in thermal communication with the region of the electricaldevice and electrical communication with a controller that is providedto monitor the inputs. The steps can comprise adjusting the electricpower (e.g., voltage and/or current, etc.) directed in or out of thethermoelectric device in response to the inputs to reduce or eliminate athermal gradient created during operation of the electrical deviceacross the temperature-sensitive region. These steps can be repeated orcycled as the electrical device continues operating. In someembodiments, these steps can continue even after operation if a thermalgradient still exists due to residual heat in the electrical device.

In some embodiments, a method of thermally managing an electrical deviceis provided that comprises connecting a thermoelectric device to acontrol system for thermally managing an electrical device, placing thethermoelectric device in thermal communication with an electricalconductor of the electrical device, and connecting a sensor to thecontrol system and the electrical device.

Discussion of the various embodiments herein has generally followed theembodiments schematically illustrated in the figures. However, it iscontemplated that the particular features, structures, orcharacteristics of any embodiments discussed herein may be combined inany suitable manner in one or more separate embodiments not expresslyillustrated or described. In many cases, structures that are describedor illustrated as unitary or contiguous can be separated while stillperforming the function(s) of the unitary structure. In many instances,structures that are described or illustrated as separate can be joinedor combined while still performing the function(s) of the separatedstructures.

Various embodiments have been described above. Although the inventionshave been described with reference to these specific embodiments, thedescriptions are intended to be illustrative and are not intended to belimiting. Various modifications and applications may occur to thoseskilled in the art without departing from the spirit and scope of theinventions described herein.

What is claimed is:
 1. A thermal management system configured to managetemperature in a temperature-sensitive region of an electrical device,the system comprising: a thermoelectric device configured to transferthermal energy between a main surface and a waste surface uponapplication of electric power to the thermoelectric device, wherein themain surface of the thermoelectric device is in thermal communicationwith a temperature-sensitive region of an electrical device; a pluralityof sensors configured to provide inputs corresponding to a thermalgradient created during operation of the electrical device across thetemperature-sensitive region; and a controller programmed, duringoperation of the electrical device, to: receive the inputs from theplurality of sensors to monitor the thermal gradient created duringoperation of the electrical device across the temperature-sensitiveregion; adjust electric power delivered to the thermoelectric devicebased on the thermal gradient such that thermal energy transferred to oraway from the temperature-sensitive region of the electrical devicereduces or eliminates the thermal gradient created during operation ofthe electrical device across the temperature-sensitive region; monitorelectric current directed in or out of the electrical device; and adjustelectric power delivered to the thermoelectric device to reduce oreliminate the thermal gradient created during operation of theelectrical device across the temperature-sensitive region at least inpart based on the electric current directed in or out of the electricaldevice.
 2. The thermal management system of claim 1, further comprisinga plurality of thermoelectric devices in thermal communication with aplurality of temperature-sensitive regions of the electrical device,wherein a main surface of each thermoelectric device of the plurality ofthermoelectric devices is in substantial thermal communication with acorresponding temperature-sensitive region of the plurality oftemperature-sensitive regions, and wherein the controller is programmedto independently adjust electric power delivered to each thermoelectricdevice based on a thermal gradient created during operation of theelectrical device across the corresponding temperature-sensitive regionsuch that the thermal energy transferred to or away from thecorresponding temperature-sensitive region of the electrical devicereduces or eliminates the thermal gradient created during operation ofthe electrical device across the corresponding temperature-sensitiveregion.
 3. The thermal management system of claim 1, wherein electricpower delivered to the thermoelectric device to reduce or eliminate thethermal gradient created during operation of the electrical deviceacross the temperature-sensitive region is adjusted between two or morenonzero levels of electric power.
 4. The thermal management system ofclaim 1, wherein the controller is further programmed to monitor athermal gradient produced as a result of the thermal energy transferredto or away from the temperature-sensitive region of the electricaldevice and to adjust electric power delivered to the thermoelectricdevice such that the thermal gradient produced as a result of thethermal energy transferred to or away from the temperature-sensitiveregion of the electrical device reduces or eliminates the thermalgradient created during operation of the electrical device across thetemperature-sensitive region.
 5. The thermal management system of claim1, wherein the thermoelectric device comprises a first operating modeand a second operating mode, wherein in the first operating mode, thethermoelectric device is configured to transfer a maximum amount ofthermal energy allowed by the thermoelectric device, and wherein in thesecond operating mode, the thermoelectric device is configured totransfer an amount of thermal energy different from the maximum amountsuch that a thermal gradient created by the transfer of thermal energybalances with the thermal gradient created during operation of theelectrical device across the temperature-sensitive region to reduce oreliminate a resultant thermal gradient across the temperature-sensitiveregion.
 6. The thermal management system of claim 1, wherein thecontroller is further programmed to monitor at least one of: temperatureof the electrical device, charge state of the electrical device, healthof the electrical device, voltage of the electrical device, resistanceof the electrical device, load on the electrical device, temperature ofan environment, weather forecast, time of day, terrain information, andgeometry of the temperature-sensitive region.
 7. The thermal managementsystem of claim 1, wherein the controller is integrated with a batterymanagement system configured to administer control functions to abattery pack.
 8. The thermal management system of claim 1, wherein theelectrical device comprises a battery, and the temperature-sensitiveregion is a cell of the battery.
 9. The thermal management system ofclaim 1, wherein the thermal gradient across the temperature-sensitiveregion of the electrical device is reduced to less than or equal toabout 10 degrees C. during operation of the electrical device.
 10. Thethermal management system of claim 1, wherein the thermoelectric deviceis configured to be powered by the electrical device.
 11. The thermalmanagement system of claim 1, wherein the controller is furtherprogrammed to adjust electric power delivered to the thermoelectricdevice based on the thermal gradient created during operation of theelectrical device to reduce or eliminate the thermal gradient createdduring operation of the electrical device across thetemperature-sensitive region.
 12. The thermal management system of claim1, wherein the thermal gradient created during operation of theelectrical device across the temperature-sensitive region of theelectrical device continually decreases in temperature from a zone ofthe electrical device proximate to an electrical conductor of theelectrical device to a zone of the electrical device farthest away tothe electrical conductor, and wherein a thermal gradient produced as aresult of the thermal energy transferred to or away from thetemperature-sensitive region of the electrical device continuallyincreases in temperature from the zone of the electrical deviceproximate to the electrical conductor to the zone of the electricaldevice farthest away to the electrical conductor to reduce or eliminatethe thermal gradient created during operation of the electrical deviceacross the temperature-sensitive region.
 13. The thermal managementsystem of claim 12, wherein the electrical device comprises a batterycell, and wherein the thermal gradient created during operation of theelectrical device across the temperature-sensitive region of theelectrical device continually decreases in temperature to the thermalgradient produced as a result of the thermal energy transferred to oraway from the temperature-sensitive region of the electrical deviceincreasing in temperature when the battery cell is substantially at fullcharge.
 14. The thermal management system of claim 12, wherein thethermal gradient produced as a result of the thermal energy transferredto or away from the temperature-sensitive region of the electricaldevice increases inversely to the thermal gradient created duringoperation of the electrical device across the temperature-sensitiveregion of the electrical device decreasing.
 15. The thermal managementsystem of claim 1, wherein the thermal gradient created during operationof the electrical device across the temperature-sensitive region of theelectrical device continually increases in temperature from a zone ofthe electrical device proximate to an electrical conductor of theelectric device to a zone of the electrical device distal to theelectrical conductor, and wherein a thermal gradient produced as aresult of the thermal energy transferred to or away from thetemperature-sensitive region of the electrical device continuallydecreases in temperature from the zone of the electrical deviceproximate to the electrical conductor to the zone of the electricaldevice distal to the electrical conductor to reduce or eliminate thethermal gradient created during operation of the electrical deviceacross the temperature-sensitive region.
 16. The thermal managementsystem of claim 15, wherein the electrical device comprises a batterycell, and wherein the thermal gradient created during operation of theelectrical device across the temperature-sensitive region of theelectrical device continually increases in temperature to the thermalgradient produced as a result of the thermal energy transferred to oraway from the temperature-sensitive region of the electrical devicedecreasing in temperature when the battery cell is substantially atdepletion.
 17. The thermal management system of claim 15, wherein thethermal gradient produced as a result of the thermal energy transferredto or away from the temperature-sensitive region of the electricaldevice decreases substantially inversely to the thermal gradient createdduring operation of the electrical device across thetemperature-sensitive region of the electrical device increasing. 18.The thermal management system of claim 1, wherein the thermal gradientcreated during operation of the electrical device across thetemperature-sensitive region of the electrical device continuallychanges in temperature from a zone of the electrical device proximate toan electrical conductor of the electric device to a zone of theelectrical device distal to the electrical conductor inversely to acontinual change in temperature from the zone of the electrical deviceproximate to the electrical conductor to the zone of the electricaldevice distal to the electrical conductor associated with a thermalgradient produced as a result of the thermal energy transferred to oraway from the temperature-sensitive region of the electrical device. 19.The thermal management system of claim 1, wherein the main surface ofthe thermoelectric device is in substantial thermal communication withan electrical conductor of the electrical device, wherein the electricalconductor is configured to deliver electric power to or from theelectrical device, and wherein the electrical conductor is capable ofserving as a conduit for conducting thermal energy between thetemperature-sensitive region of the electrical device and thethermoelectric device.
 20. The thermal management system of claim 19,wherein two or more electrical conductors comprise the electricalconductor, and wherein the two or more electrical conductors arepositioned on a same surface of the electrical device.
 21. A thermalmanagement system configured to manage temperature of an electricaldevice, the system comprising: a thermoelectric device configured totransfer thermal energy between a main surface and a waste surface viaelectric power applied to the thermoelectric device, wherein the mainsurface of the thermoelectric device is in thermal communication with ofan electrical conductor of an electrical device, the electricalconductor configured to deliver electric power to or from the electricaldevice; a plurality of sensors configured to provide inputscorresponding to a thermal gradient of the electrical device; and acontroller programmed to: receive the inputs from the plurality ofsensors to monitor the thermal gradient of the electrical device; adjustelectric power delivered to the thermoelectric device based on thethermal gradient such that thermal energy transferred to or away fromthe electrical device reduces or eliminates the thermal gradient of theelectrical device; monitor electric current directed in or out of theelectrical device; and adjust electric power delivered to thethermoelectric device to reduce or eliminate the thermal gradient of theelectrical device created during operation of the electrical device atleast in part based on the electric current directed in or out of theelectrical device.
 22. The thermal management system of claim 21,further comprising a plurality of thermoelectric devices in thermalcommunication with a plurality of electrical conductors of theelectrical device, the plurality of electrical conductors comprising theelectrical conductor, wherein a main surface of each thermoelectricdevice of the plurality of thermoelectric devices is in substantialthermal communication with a corresponding electrical conductor of theplurality of electrical conductors, and wherein the controller isprogrammed to independently adjust electric power delivered to eachthermoelectric device based on a thermal gradient across the electricaldevice such that the thermal energy transferred to or away from thecorresponding electrical conductors of the electrical device reduces oreliminates the thermal gradient of the electrical device.
 23. Thethermal management system of claim 21, wherein the electrical devicecomprises a battery cell, and the controller is programmed to adjustelectric power delivered to the thermoelectric device such that thermalenergy transferred to or away from the electrical device reduces oreliminates the thermal gradient across the battery cell.
 24. A thermalmanagement system configured to manage temperature of an electricaldevice, the system comprising: a plurality of thermoelectric deviceseach configured to transfer thermal energy between a main surface and awaste surface via electric power applied to the thermoelectric device,wherein the main surface of each thermoelectric device is in thermalcommunication with of one or more electrical conductors of an electricaldevice; and a controller programmed to: monitor a thermal gradient ofthe electrical device; adjust electric power delivered to the pluralityof thermoelectric devices based on the thermal gradient such thatthermal energy transferred to or away from the electrical device reducesor eliminates the thermal gradient of the electrical device; monitorelectric current directed in or out of the electrical device; and adjustelectric power delivered to the plurality of thermoelectric devices toreduce or eliminate the thermal gradient of the electrical devicecreated during operation of the electrical device at least in part basedon the electric current directed in or out of the electrical device. 25.A thermal management system configured to manage temperature of abattery cell, the system comprising: a thermoelectric device configuredto transfer thermal energy between a main surface and a waste surfacevia electric power applied to the thermoelectric device, wherein themain surface of the thermoelectric device is in thermal communicationwith an electrical conductor of a battery cell; a sensor configured toprovide an input corresponding to a thermal gradient of the batterycell; and a controller programmed to: receive the input from the sensorto monitor the thermal gradient of the battery cell; adjust electricpower delivered to the thermoelectric device based on the thermalgradient such that thermal energy transferred to or away from thebattery cell reduces or eliminates the thermal gradient of the batterycell; monitor electric current directed in or out of the battery cell;and adjust electric power delivered to the thermoelectric device toreduce or eliminate the thermal gradient of the battery cell createdduring operation of the battery cell at least in part based on theelectric current directed in or out of the battery cell.